Backward monitoring using a wide angle camera (obstacle detection) cannot implement detection of the height of a static object and the height of an object. Further, a monocular camera cannot acquire distance information. On the other hand, a problem with detection of an obstacle using a distance sensor is that because the distance sensor is designed to detect a large area at a time, the bearing resolution of the distance sensor is low.
Conventionally, patent reference 1 discloses a related art technique as such a technique of detecting an obstacle.